Process for preparing durable press fabrics which can be dyed with acid dyes

ABSTRACT

This invention consists of the preparation of durable press fabrics with basic moieties crosslinked into the fabric. As a consequence of these basic moieties, these fabrics can now be dyed with acid dyes even though they are crosslinked. Heretofore, crosslinked cotton fabrics could not be dyed satisfactorily with acid dyes. This fabric basicity is achieved by the use of reactive alcohol additives containing amine groups such as diethanolamine, triethanolamine, monoethanolamine and 2dimethylaminoethanol.

United "States Patent [191 Harper, Jr. et al. I

[ Apr. 30, 1974 1 PROCESS FOR PREPARING DURABLE PRESS FABRICS WHICH CAN BE DYED WITH ACID DYES [75] Inventors: Robert J. Harper, Jr.; Gloria A.

' Gauti-eaux, both of Metairie;

Eugene J. Blanchard, New Orleans, all of La.

[73] Assignee: The United States of America as represented by the Secretary of Agriculture, Washington, DC.

[22] Filed: Jan. 24, 1972 [21] App]. No.1 220,416

[52] US. Cl. 8/18, 8/17, 8/31, l 8/1 0O,8/185,8/186 [5l] Int. Cl D06m 5/00 [58] Field of Search 8/185, 17, 18, 31, 100, 8/186 [56] References Cited UNITED STATES PATENTS 3,125,403 3/1964 Senger 8/18 X 2,950,553 8/1960 Hurwitz 8/l85 3,663,159 5/1972- Gordon 8/185 3,407,026 10/1968 Mauldin 3/185 X 2,957,746 10/1960 Buck et al 3/185 X 2,203,493 6/]940 Evans fit al. 8/100 X 3,142,529 7/1964 Freyermuth et al. 8/18 3,046,075 7/1962 Kantner et al. 8/18 Primary Examinerl-Ierbert B. Guynn Attorney, Agent, or Firm-M. Howard Silverstein; Max D. Hensley [57] ABSTRACT 10 Claims, N0 Drawings PROCESS FOR PREPARING DURABLE PRESS FABRICS WHICH CAN BE DYED WITH ACID DYES A non-exclusive, irrevocable, royalty-free license in the invention herein described,-throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted tothe Government of the United States of America.

This invention relates to treatments which impart wrinkle resistance to cellulosic textile materials. In particular, it relates to providing a method by which cotton fabrics may be finished so that they will be wrinkle resistant and will have characteristics so that they can then be dyed with acid dyes.

In essence, this invention relates to the use of ethanolamines or alcohol amines as reactive additives in finishing. The normal resin formulation and catalyst are used as the components in the finishing bath together with the desired amount of alcohol amine. The only other component is an acid with which the pH of the finishing bath is adjusted to compensate for the basicity of the amine used as a reactive additive. The fabric is then dried and cured in the usual manner. The crosslinked fabrics are then laundered to yield a durablepress fabric which contains amine groups crosslinked into the fabric matrix. By durable-press is meant a fabric which is smooth and does not requireironing on removal from a tumble drier. By wash-wear is meant a fabric which on removal from a tumble drier requires only touch-up ironing to be smooth. In terms of wrinkle-recovery angle (WRA) cotton fabrics with WRA greater than 270 can be considered durable-press while those between 24-270 may be considered washwear should they have the desired smoothness consid ered above. As a consequence of these basic groups, the fabric now possesses good affinity for acid dyes.

Various amounts and types of alcohol amines can be used as reactive additives for the purpose described. In general, the effective range studied has been from about 0.5% to about 5% of the alcohol amine in'the pad bath. The preferred range of operation appears to be from about l2%. The higher amounts of amine in the formulation sometimes leads to discoloration problems and this is another reason for giving preference to low concentrations in the pad bath. A variety of alcohol amines have been utilized. From the viewpoint of dye uptake, there are some indications that the depth of the dye shade seems to increase with the basicity of the amine fixed on the fabric. In this respect, tertiary amines are better than secondary amines and secondary amines are better than primary amines. Furthermore, from the viewpoint of fabric discoloration, tertiary amines seem to cause less fabric discoloration than secondary, which in turn seem to cause less discoloration than primary. Examples of the tertiary amines used in this ,work are triethanolamine and 2- dimethylaminoethanol. An example of the secondary amine is diethanolamine and an example of a primary amine is monoethanolamine.

The crosslinking agent preferred with this method appears to be dimethylol dihydroxyethyleneurea. Although other agents are also effective, the preceding agent is particularly effective because it has four'N- methylol groups available for crosslinking. As a result, if one N-methylol moietyis used in reaction with the reactive additive, three other sites are still available for crosslinking cotton. As a consequence, it is possible to obtain fabrics with good durable-press rating and wrinkle recovery values and with a certain amount of amine groups attached to the fabric. Because of the amine groups, the fabric can now be dyed with acidic dyes.

Thus, one should consider three cotton fabrics. One fabric is untreated, the other is crosslinked in a conventional manner using crosslinking agent, metal salt catalyst and no reactive amine additive. The third fabric is crosslinked using crosslinking resin, metal salt catalyst, reactive alcohol amine and sufficient acid to neutralize the alcohol amine. Examples of the alcohol amines have been previously mentioned.

The crosslinked series of fabrics are laundered, then dyed in a dye bath containing an acid dyestuff and the other normal reagents commonly found in an acidic dye bath. After the fabrics are dyed in the usual manner, the resultant fabrics are rinsed and laundered.

While the untreated cotton and crosslinked control with no additive have poor affinity for the acid dyestuff, the samples of fabrics containing the amine groups are dyed a significantly deep color with the acid dyestuff. Examples of some typical acid dyes with which this approach has found merit are:

Acid Red 1 (Color Index 18050) Acid Blue 158 (Color Index 14880) Acid Red 30 (Color Index 17035) Acid Blue 9 (Color Index 42090) By contrast, the fabric crosslinked in the normal manner shows poor dye receptivity. This would be true not onlywith respect to the acid dyes used in this work but for acid dyes in general. The value of this process is that it permits the dyeing of fabrics and garments after a crosslinking finish has been applied to the fabric. This may have certain distinct marketing, processing, and technical advantages. For example, it is possible to convert white goods to a different color should a demand arise for certain special .colored fabrics. Such an option of selling fabrics either as white or colored goods might be advantageous for inventory control. Also, the dyeing of fabrics after crosslinking could be utilized to yield dye shades not normally available due to the high temperatures used in the curing of certain textile goods. As a consequence, this procedure circumvents the problems related to dyestuff sublimation and metal salt catalysts. Finally, the ability to adjust the dye shade after crosslinking adds an element of flexa- I bility not currently available to the finisher.

In general terms, the process of this invention starts with the incorporation of the alcoholic amine in the normal pad bath solution together with sufficient acid to neutralize the basicity introduced by the amine. From this point on, the fabric is finished in a standard manner according to contemporary textile practice. This method can be used with a number of textile formulations, the only requirement being that an approdiethanolamine (B) CH,CH OH N-CH CH OH monoethanolamine (C) HOCH CH N and Z-dimethylaminoethanol (D) NCH,CH OH Other agents can easily be visualized. The only requirements would be that the group carry a hydroxyl group for reaction with the crosslinking agent and a basic amine moiety for imparting a basic character to the fabric.

To summarize, this invention can best be viewed as a process for imparting receptivity for acid dyes to crosslinked cotton fabrics. Normally cotton fabrics either crosslinked or non-crosslinked have poor receptivity for acid dyes. The improvement consists in the use of hydroxyamines as coreactants in normal crosslinking systems. As a consequence, crosslinked fabrics are obtained containing pendant amine groups fixed on the fabrics. Dye procedures can now be applied to these fabrics using acid dyes which would be substantive to a basic substrate. Neither cotton crosslinked in the normal manner nor untreated cotton fabrics have much substantivity or afiinity for acid dyestuffs.

Only the basic formulations have been used in these examples. Variations using softeners, wetting agents, polymer additives, and various finishing systems are readily accessible for anyone skilled in the art of textile finishing.

EXAMPLE'l One set of cotton printcloth was padded with a solution containing 9 parts dimethylol dihydroxyethyleneurea, 0.5 parts zinc nitrate hexahydrate and 90.5 parts water. The fabric was dried for 7 minutes at 60C and cured for minutes at 160C. The fabric was then laundered and tumble-dried.

A second set of cotton printcloth was finished with modified formulations and cured in the same manner. The modifications consisted of replacing an equivalent number of parts of water with the same number of parts of base and sufficient neutralizing acid (HCl) to maintain the pH at less than S. The bases used were triethanolamine (0.5, 1, 2, 3, 5 parts in the padding solution);

appearance, wrinkle recovery values ranging from 250 to 280, and grafts on the fabric containing these attached amine groups. The presence of these amine grafts were indicated by the fact that these reactive additives led to an increase both in total fabric add-on as well as in bound nitrogen on the fabric.

Small swatches of the two sets treated above, together with an untreated cotton control were then dyed in a dye bath using acid blue 158 (1.2% dye 0.8% glacial acetic acid). The samples were inserted in the dye bath at C, the temperature raised to 65C over a 20 minute period, cooled to C over a 15 minute period, heated to 80C over a 25 minute period, and cooled to 50C over a 40 minute period.

Samples were then rinsed several times in distilled water, regular water, and then washed on warm setting in washing machine.

The fabrics were also dyed using the same type of bath (but no acetic acid) and a similar procedure as in the previous case. Again, of the series checked, the fabrics which contained the amine group dyed a dark blue while the untreated cotton and crosslinked control dyed to only a very slight extent. The fact that the crosslinked control and untreated cotton have little affinity for the acid dyes, while the crosslinked fabrics with the reactive additives show good takeup of dye, attests to the overall effectiveness of the procedure. This procedure consists of a method for producing crosslinked cellulosic fabrics with basic groups and then dyeing the fabrics with acid dyes.

EXAMPLE 2 Swatches of the samples reported in Example 1 were inserted in a dye bath containing 1% Acid Red 30 (Color Index C1 17035). The bath was heated to C for 45 minutes, cooled to 50C over a period of 20 minutes, heated to C over a period of 40 minutes and then cooled to 40C. The samples were then rinsed repeatedly in distilled water and then warmed to 40C in distilled water. The fabrics were then tumble-dried. While the untreated cotton and crosslinked cottons were dyed a faint to light pink, the fabrics with the amine groups attached were dyed red. The color became a progressively deeper shade of red with increasing amounts of base fixed on the fabric. This occurred with the following series of amine reactive additives: monoethanolamine, diethanolamine, triethanolamine, and Z-dimethylethanolamine. These samples provide further examples of the effectiveness of the overall process in producing cotton fabrics that are crosslinked and yet dyeable with acid dyes.

EXAMPLE 3 Samples of fabrics from Example 1 were inserted in a dye bath (50C) containing 1.25% Acid Blue 9 (Color lndex 42090) and 1% glacial acetic acid. The samples were heated to 75C over a periodof 30 minutes, allowed to cool for a period of 30 minutes, heated to 75C over a period of 30 minutes, and then allowed to cool for 15 minutes. The samples were then repeatedly washed in distilled water. The untreated cotton and the crosslinked control weredyed a very faint blue. The fabrics with the amines crosslinked on the fabric were dyed a bright to dark blue as the amount of amine crosslinked on the fabric increased. Included in this group were series in which the amines were monoeth'anolamine, diethanolamine, triethanolamine, and Z-dimethylethanolamine. Again, the fact that the various samples were dyed a deep shade with the acid dye clearly illustrates the effectiveness of the overall procedure in which a crosslinked fabric with attached amine groups is produced in the first step of the process and the fabrics are then dyed with an acid dye in the second step of the process.

EXAMPLE 4 In this case, the triethanolamine samples, the standard crosslinked fabric and the untreated cotton from Example 1 were dyed with a dye bath prepared from 1.5 parts Acid Red (Color Index 18050) and 1 part glacial acetic acid and 97.5 parts of water. The fabrics were inserted in the bath at room temperature, the temperature raised to 45C, cooled to 35C, raised to 55C, cooled to 45C, and raised to 80C. Time periods with each temperature change were approximately 30 minutes. The fabrics were then rinsed repeatedly in distilled water including one period in which the bath was raised to 70C. While the untreated cotton and crosslinked control were dyed a faint pink, the fabrics with triethanolamine attached were dyed'a deep red. The color shade became deeper with increasing amounts of the amine crosslinked on the fabric.

EXAMPLE 5 equivalent number of parts of water with the same number of parts of base and sufficient neutralizing acid to maintain the pH of treating baths at less than 5. The bases used were triethanolamine (05,1, and 3 parts in the padding solution) and 2-dimethylaminoethanol (0.5, 1, and '3 parts in the padding solution). After these various samples were prepared and laundered, they represented a series of fabrics in which the fabrics had good wash-wear or durable-press appearance, and high wrinkle recovery values. Those samples containing alcohol amines in the formulation had grafts on the fabrics containing thev previously mentioned amine groups. Samples of these fabrics, together with an un-' treated polyester-cotton, were then dyed using the dye bath (1% Acid Red 30, Color Index 17035) and dye procedure described in Example 2. After the fabrics had been washed in the same manner as in Example 2, the fabrics were inspected. The untreated polyestercotton and crosslinked polyester-cotton were dyed a pale pink. The polyester-cottons with triethanolamine and Z-dimethylethanolamine were dyed red with the a dark blue with the fabrics which were treated with the color becoming a deep red in the cases in which a larger amount of amine was crosslinked into the fabric. Since the polyester component does not dye, the

higher level of amine in the finishing formulation.

EXAMPLE 6 Cotton fabric was padded with a moist cure formulation, the moisture content was reduced to 7% using air drying conditions. The fabric was sealed, in a plastic bag and allowed to remain in the bag for 24 hours at room temperature. The fabric was then laundered. The moist cure formulation was prepared using 13.5% dimethylol dihydroxyethyleneurea, sufficient hydrochloric acid to lower pH to l, and the remainder water. In addition to the above formulation, formulations were prepared using various amounts and types of ethanolamines in addition to the crosslinking agent and hydrochloric acid. The amounts of amine used were 1% triethanolamine, l% Z-dimethylaminoethanol, 3% triethanolamine, 3% diethanolamine, 3% monoethanolamine, and 3% Z-dimethylaminoethanol. These two formulations yielded a series of fabrics with the moist cure finish and fabrics with the moist cure finish with grafted amino moieties.

Samples of these fabrics, together with an untreated cotton fabric, were then dyed (with 1% Acid Red 30, Color Index 17035) using the dye procedure, bath and rinse method described in Example 2. While the moist cure fabric with no amine additive and the untreated cotton dyed a light pale pink, the fabrics treated with moist cure plus amines in the formulation were dyed a red to a deep red. The deep red shade was the sample in which 3% of the various ethanolamines were used in the finishing formulation. Analogous results were ob served with samples of the fabric described in this example and dyed with the dye bath, procedure and wash procedure described in Example 3. The dye in this case was Acid Blue 9 (Color Index 42090). Again, the samples with the amine grafts were dyed a deep blue, whereas the untreated cotton and moist cure crosslinked control were dyed a pale blue. These results show that the overall procedure of crosslinking in a basic group and then dyeing the fabric with an acid dye to be applicable to another finishing system than the normal pad-dry-cure process. This tends to further indicate the broader scope of the overall process.

EXAMPLE 7 The same process was repeated as in Example 6 except that -50 polyester-cotton fabric rather than an all-cotton fabric was utilized. The particular amines used in preparing the formulations included 3% triethanolamine and 3% 2-dimethylaminoethanol.

I These samples as well as the untreated polyestercotton were dyed with Acid Red 1 (Color Index 18050). The dye bath contained 1 part Acid Red 1, 0.5 parts of glacial acetic acid and the remainder water. The bath temperature was raised to C over a period of 25 minutes, allowed to cool to 40C over a period of minutes, heated to 75C over a period of minutes, and then cooled. The samples were rinsed repeatedly in distilled water. The polyester-cotton with the moist cure treatment and grafted amine groups were dyed a deep red. By contrast, the untreated polyestercotton was tinged a very pale pink.

EXAMPLE 8 Samples of the fabrics from Example 6 were dyed with Acid Red 1 (Color Index 18050) using the dye bath concentrations, procedure and rinse procedure described in Example 7. The samples with the moist cure finish and amine grafts were a bright pink to a deep red depending upon the amount of amine used in the finishing formulation. By contrast, the untreated cotton or crosslinked control was dyed only a very pale pink.

Again, these results further substantiate the ability of the amine grafts to yield a crosslinked fabric which can be dyed with an acid dye regardless of the finishing formulation.

EXAMPLE 9 Cotton fabrics were given an easy cure finish and then heated in a forced draft oven at 60C. One was heated for seven minutes, the other for 9 minutes. The finishing bath for the easy cure finish was prepared by using 13.5 parts dimethylol dihydroxyethyleneurea, 1 part hydrochloric acid and 85.5 parts water. Two other series of fabrics were run in which 3% triethanolamine and 3% Z-dimethylaminoethanol were added to the finishing formulation together with sufficient acid to reduce pH to the same level as the control treatment without additive. After the samples were washed, they yielded two series (7 and 9 minute cures) of easy cure fabrics with amine grafts and appropriate controls. The samples, together with an untreated cotton fabric, were then dyed with Acid Red 1 (Color Index 18050); using the same dye bath, procedure, and rinse conditions described in Example 7. While the control (regular easy cure" finish) was dyed a very pale pink, the samples with the amine graft were dyed a deep red. This is another example of the effect of the amine grafts in preparing a crosslinked fabric which can be dyed with an acid dye.

We claim:

1. A process for imparting durable press performance and dyeability with an acid dye to a cellulosic fabric subsequent to crosslinking thereof, comprising:

a. impregnating a cellulosic fabric with an aqueous solution containing about from 1 to 15 weight percent of dimethylol dihydroxyethyleneurea as a crosslinking agent for cellulose, about from 0.5 to 4.0 weight percent of an acidic reagent for catalyzing the crosslinking reaction between the fabric cellulose and said crosslinking agent, about from 0.2 to 5.0 weight percent of an alcoholic amine selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, and 2 dimethylethanolamine, and sufficient acid to neutralize the basicity of said amine;

b. drying the impregnated fabric from step (a) at a temperature of about from 25C. to C. for a period of about from 2 minutes to 24 hours;

c. curing the dry fabric from step (b) at a temperature of about from C. to C. for a period of about from 30 seconds to 20 minutes to effect crosslinking of the fabric; and

d. dyeing the crosslinked fabric from step (c) with an acid dye.

2. The process of claim 1 amine is monoethanolamine.

3. The process of claim 1 amine is diethanolamine.

4. The process of claim 1 amine is triethanolamine.

5. The process of claim 1 wherein the alcoholic amine is 2-dimethylethanolamine.

6. The process of claim 1 wherein the acidic catalyst is zinc nitrate hexahydrate.

7. The process of claim 1 wherein the acid dye is Acid Blue 9.

8. The process of claim 1 wherein the acid dye is Acid Blue 158.

9. The process of claim I wherin the acid dye is Acid Red 1.

'10. The process of claim 1 wherein the acid dye is Red 30.

wherein the alcoholic wherein the alcoholic wherein the alcoholic 

2. The process of claim 1 wherein the alcoholic amine is monoethanolamine.
 3. The process of claim 1 wherein the alcoholic amine is diethanolamine.
 4. The process of claim 1 wherein the alcoholic amine is triethanolamine.
 5. The process of claim 1 wherein the alcoholic amine is 2-dimethylethanolamine.
 6. The process of claim 1 wherein the acidic catalyst is zinc nitrate hexahydrate.
 7. The process of claim 1 wherein the acid dye is Acid Blue
 9. 8. The process of claim 1 wherein the acid dye is Acid Blue
 158. 9. The process of claim 1 wherin the acid dye is Acid Red
 1. 10. The process of claim 1 wherein the acid dye is Red
 30. 